Hairpin-like siRNA-Based Spherical Nucleic Acids

The therapeutic use of small interfering RNAs (siRNAs) as gene regulation agents has been limited by their poor stability and delivery. Although arranging siRNAs into a spherical nucleic acid (SNA) architecture to form siRNA-SNAs increases their stability and uptake, prototypical siRNA-SNAs consist of a hybridized architecture that causes guide strand dissociation from passenger strands, which limits the delivery of active siRNA duplexes. In this study, a new SNA design that directly attaches both siRNA strands to the SNA core through a single hairpin-shaped molecule to prevent guide strand dissociation is introduced and investigated. This hairpin-like architecture increases the number of siRNA duplexes that can be loaded onto an SNA by 4-fold compared to the original hybridized siRNA-SNA architecture. As a result, the hairpin-like siRNA-SNAs exhibit a 6-fold longer halflife in serum and decreased cytotoxicity. In addition, the hairpin-like siRNA-SNA produces more durable gene knockdown than the hybridized siRNA-SNA. This study shows how the chemistry used to immobilize siRNA on nanoparticles can markedly enhance biological function, and it establishes the hairpin-like architecture as a next-generation SNA construct that will be useful in life science and medical research.

Automated summary

A new hairpin-like siRNA-SNA design is introduced in this study to prevent guide strand dissociation, resulting in enhanced stability, reduced cytotoxicity, and more durable gene knockdown compared to traditional hybridized siRNA-SNAs. This novel approach significantly improves the biological function and establishes a next-generation SNA construct for life science and medical research.